Brazil, Southern and central Africa, Madagascar, Color: yellow, Hardness: 7, Refractive index: 1.54 1.55, Density: 2.65 2.66, Chemical composition: SiO2, Crystal structure: hexagonal, Origins: Widespread; best stones come from Brazil. Citrine is one of the least expensive gemstones. Even very big pieces, 50 carats and more, can be easily found on the market. Greenish-yellow and orange stones are more valuable, and heat treatment is often applied to enhance the yellow color., Yellow, brown
Brazil, Color: bi-color, violet / yellow, Hardness: 7, Refractive index: 1.54 1.55, Density: 2.65 2.66, Chemical composition: SiO2, Crystal structure: hexagonal, Lustre: vitreous, Origins: Brazil, Bolivia, Uruguay. Ametrine is a bi-color variety of quartz, Yellow, Orange, India